Crew protection system

ABSTRACT

An occupant protection apparatus includes an air bag device  20  for deploying an air bag between a steering wheel  11  and an occupant H and an impact-energy-absorption-type steering column  12  equipped with an energy-absorbing mechanism  30 , and absorbs impact energy of the occupant H during a vehicle collision event. Both the air bag device  20  and the energy-absorbing mechanism  30  are of a variable energy absorption load type. When their energy absorption loads are varied, the energy absorption loads change in the same direction.

TECHNICAL FIELD

[0001] The present invention relates to an occupant protection apparatusmounted in a vehicle and adapted to protect an occupant of the vehicleduring a vehicle collision event through absorption of impact energy ofthe occupant.

BACKGROUND ART

[0002] Occupant protection apparatus of this kind include an air bagdevice for deploying an air bag between a steering wheel and anoccupant, an impact-energy-absorption-type steering column, and acombination of the air bag device and the impact-energy-absorption-typesteering column. Another occupant protection apparatus includes an airbag device incorporated in a steering wheel and an actuator for movingforward a steering column with appropriate timing in accordance with aforward movement of a driver during a vehicle collision event so as tolessen a load that is imposed on the driver when the driver interfereswith the air bag incorporated in the steering wheel (Japanese Patent No.2596200).

[0003] Conventionally, an energy absorption load; i.e., a load to beimposed on an occupant, is set such that the impact energy of theoccupant can be absorbed in relation to a working stroke for energyabsorption. However, when the working stroke for energy absorptioncannot be set long because of restrictions on the mounting space of thevehicle, the energy absorption load is set higher as compared with thecase where the working stroke can be set long. Therefore, when collisionconditions and the occupant's physique are taken into consideration, theenergy absorption load becomes excessively high; thus, from theviewpoint of the quantity of energy absorption by an air bag device andan impact-energy-absorption-type steering column, the working stroke maybe unnecessarily long and thus fails to be effectively exploited (whenthe impact energy of an occupant is small, such an insufficientexploitation of the working stroke arises). Further, setting the energyabsorption load to an increased level means that the load imposed on anoccupant becomes high. If energy can be absorbed while the occupant issupported with load of a slightly lower level, impact energy can beeffectively absorbed while the occupant is subjected to a gentler load.

DISCLOSURE OF THE INVENTION

[0004] In view of the foregoing, an object of the present invention isto effectively absorb the impact energy of an occupant under a gentleenergy absorption load; i.e., while supporting the occupant by means ofa gentle load, during a vehicle collision event.

[0005] An occupant protection apparatus according to the presentinvention comprises an air bag device for deploying an air bag between asteering wheel and an occupant, and an impact-energy-absorption-typesteering column, and absorbs impact energy of the occupant during avehicle collision event. The air bag device and theimpact-energy-absorption-type steering column are of a variable energyabsorption load type. When the energy absorption loads of the air bagdevice and the impact-energy-absorption-type steering column are varied,the energy absorption loads are varied in the same direction. The energyabsorption loads may be varied stepwise or continuously.

[0006] The above configuration yields, for example, the followingeffect: when a vehicle speed upon occurrence of a vehicle collision;i.e., a collision speed, is higher than an assumed value, the energyabsorption loads of the air bag device and theimpact-energy-absorption-type steering column can be varied in the sameincreasing direction; and when the collision speed is lower than theassumed value, the energy absorption loads of the air bag device and theimpact-energy-absorption-type steering column can be varied in the samedecreasing direction.

[0007] Thus, as compared with the case where at least either the energyabsorption load of the air bag device or that of theimpact-energy-absorption-type steering column is constant; i.e., whereat least either the air bag device or the impact-energy-absorption-typesteering column is of a fixed energy absorption load type, impact energycan be effectively absorbed while an energy absorption load imposed onan occupant is suppressed to a low value. This effect can be attainedwithout need to increase the working stroke of the air bag device andthat of the impact-energy-absorption-type steering column, so that theeasiness of mounting of the air bag device and theimpact-energy-absorption-type steering column onto the vehicle is notimpaired.

[0008] The present invention may be embodied in such a manner that theenergy absorption loads of the air bag device and theimpact-energy-absorption-type steering column are set low when anoccupant wears his/her seat belt, and are set high when the occupantdoes not wear his/her seat belt. In this case, since the energyabsorption loads of the air bag device and theimpact-energy-absorption-type steering column are set low when theoccupant wears his/her seat belt, and are set high when the occupantdoes not wear his/her seat belt, the impact energy of the occupant canbe reliably absorbed regardless of whether the occupant's seat belt isfastened, thereby reliably protecting the occupant.

[0009] Further, the present invention is preferably embodied in such amanner that the steering wheel comprises energy-absorbing means forabsorbing impact energy. In this case, since the steering wheel itselfhas the energy-absorbing means for absorbing impact energy, as comparedwith the case where the steering wheel does not have theenergy-absorbing means, the air bag device and theimpact-energy-absorption-type steering column can be reduced in size,and the easiness of mounting of the air bag device and theimpact-energy-absorption-type steering column onto the vehicle isimproved.

[0010] Moreover, the present invention may be embodied in such a mannerthat, in the case of a condition under which the energy absorption loadsare set low, at least one of the air bag device, theimpact-energy-absorption-type steering column, and the energy-absorbingmeans is selected to absorb impact energy.

BRIEF DESCRIPTION OF DRAWINGS

[0011]FIG. 1 is a side view schematically showing one embodiment of anoccupant protection apparatus according to the present invention;

[0012]FIG. 2 is a plan view schematically showing a steering apparatusshown in FIG. 1;

[0013]FIG. 3 is a side view of the steering apparatus shown in FIG. 2;

[0014]FIG. 4 is a vertical sectional side view showing a main portion ofFIG. 3;

[0015]FIG. 5 is a plan view of a curved plate shown in FIG. 4;

[0016]FIG. 6 is an enlarged vertical sectional front view taken alongline 6-6 of FIG. 5;

[0017]FIG. 7 is a pair of schematic performance diagrams showingperformance during a front collision event of a vehicle under thecondition that a seat belt is fastened; and

[0018]FIG. 8 is a schematic performance diagram showing performanceduring a front collision event of a vehicle under the condition that aseat belt is not fastened.

BEST MODE FOR CARRYING OUT THE INVENTION

[0019] An embodiment of the present invention will next be describedwith reference to the drawings. FIGS. 1 to 6 show an occupant protectionapparatus according to the present invention. The occupant protectionapparatus includes an air bag device 20 incorporated in a steering wheel11; an energy-absorbing mechanism 30 mounted between a steering column12 and a vehicle body (not shown); and a seat belt device 40 mountedbetween a seat 50 and the vehicle body. The occupant protectionapparatus is adapted to absorb impact energy of a driver H during afront collision event of the vehicle.

[0020] The steering wheel 11 is attached to a rear end portion of asteering shaft 13 in a manner unitarily rotatable with the steeringshaft 13, which is attached to the steering column 12 in a rotatable andaxially immovable manner. The steering wheel 11 includes a mechanicalenergy-absorbing means (the impact energy of the driver is absorbed bymeans of plastic deformation of the steering wheel itself). A rearportion of the steering column 12 is supported by a portion of thevehicle body (not shown) via an upper support bracket 14, and a frontportion of the steering column 12 is supported by a portion of thevehicle body via the energy-absorbing mechanism 30.

[0021] A front end portion of the steering shaft 13 is connected to asteering link mechanism 15. The upper support bracket 14 is attached toa portion of the vehicle body and supports the steering column 12 in afrontward breakaway manner. When a predetermined load acts on thesteering column 12 toward the front of the vehicle, the upper supportbracket 14 allows the steering column 12 to break away and movefrontward.

[0022] The air bag device 20 includes an air bag body (not shown), whichis accommodated within the steering wheel 11 in a folded condition, anda pair of inflators (not shown) capable of supplying gas to the air bagbody and whose gas supply timing is controlled by an electric controlunit ECU. During a front collision event of the vehicle, the air bagbody that is inflated and deployed between the driver H and the steeringwheel 11 receives the driver H, thereby absorbing the impact energy ofthe driver H. In the air bag device 20, the electric control unit ECUcontrols the timing of supplying gas by means of the paired inflators,whereby an energy absorption load is continuously adjustable, orvariable.

[0023] The energy-absorbing mechanism 30 also serves as a supportmechanism for supporting a front portion of the steering column 12 andincludes, as shown in FIGS. 2 to 4, a support bracket 31; a support pin32; a lower support bracket 33; a curved plate 34, which serves as anenergy-absorbing member; and an engagement device 35, which serves as adeformation-characteristic-varying means.

[0024] The support bracket 31 assumes a portal shape as viewed from itsfront or rear side and is fixedly attached to the steering column 12such that lower end portions of two mutually facing side wall portions31 a are fixed on an upper circumferential portion of the steeringcolumn 12. An elongated hole 31 b is formed in each of the two side wallportions 31 a of the support bracket 31 in such a manner as to extendobliquely upward toward the rear side from a central region of the sidewall portion 31 a and such that the two elongated holes 31 b face eachother. Each of the elongated holes 31 b consists of a circular holeportion 31 b 1, which serves as a proximal end portion; a straplike holeportion 31 b 2, which extends obliquely upward toward the rear side fromthe circular hole portion 31 b 1; and a narrow-width portion 31 b 3,which connects the circular hole portion 31 b 1 and the straplike holeportion 31 b 2. The straplike hole portion 31 b 2 has a widthsubstantially equal to the diameter of the circular hole portion 31 b 1.

[0025] The support pin 32 is attached to the lower support bracket 33,which is fixedly attached to a portion of the vehicle body, whileextending through the elongated holes 31 b of the support bracket 31.While being attached to the lower support bracket 33, the support pin 32supports a front end portion of the steering column 12 to a portion ofthe vehicle body via the support bracket 31 such that the steeringcolumn 12 is rotatable along a vertical plane. In the condition shown inFIGS. 3 and 4, the support pin 32 is inserted in the circular holeportions 31 b 1 of the respective elongated holes 31 b of the supportbracket 31. In response to a movement of the support pin 32 relative tothe support bracket 31, the support pin 32 can move rearward beyond thenarrow-width portions 31 b 3 and along the straplike hole portions 31 b2.

[0026] The curved plate 34 is formed of a plate having a predeterminedwidth by curving a rear end portion of the plate by about 360 degreesand includes an upper wall portion 34 a, a lower wall portion 34 b, anarcuate wall portion 34 c, and an upright wall portion 34 d. The upperand lower wall portions 34 a and 34 b face each other while apredetermined distance is maintained therebetween. The arcuate wallportion 34 c connects the rear ends of the upper and lower wall portions34 a and 34 b together. The upright wall portion 34 d stands verticallyfrom the front end of the lower wall portion 34 b.

[0027] The curved plate 34 is welded to the support bracket 31 whilebeing positioned by means of a plurality of pins 31 c, which areimplanted in the side wall portions 31 a of the support bracket 31 insuch a manner as to surround the circular hole portions 31 b 1 of theelongated holes 31 b. Within the support bracket 31, the curved plate 34surrounds the support pin 32 as follows: the upright wall portion 34 dis located on the front side of the support pin 32; and the arcuate wallportion 34 c is located on the rear side of the support pin 32 whileextending across the straplike hole portions 31 b 2 of the elongatedholes 31 b as viewed from the side of the support bracket 31.

[0028] As shown in FIGS. 5 and 6, in the curved plate 34, upper andlower groove portions 34 e 1 and 34 e 2 are formed on the upper wallportion 34 a in such a manner as to extend longitudinally at a widthwisecentral portion; a circular engagement hole 34 e 3 is formed in theupper wall portion 34 a at rear end portions of the groove portions 34 e1 and 34 e 2; and a groove 34 e 4 is formed on the upper wall portion 34a in such a manner as to connect the engagement hole 34 e 3 to thegroove portions 34 e 1 and 34 e 2.

[0029] The engagement device 35 includes a solenoid 35 a and a shear pin35 b, which advances and retreats through control of energization of thesolenoid 35 a. The solenoid 35 a is fixedly attached to a front endportion of an upper wall portion 31 d of the support bracket 31. Theengagement device 35 is attached to the support bracket 31 such that theshear pin 35 b extends through the upper wall portion 31 d of thesupport bracket 31 and faces the engagement hole 34 e 3 of the upperwall portion 34 a of the curved plate 34 in such a manner as to be ableto advance and retreat. The shear pin 35 b is tapered such that itsdiameter gradually reduces toward its tip.

[0030] In the engagement device 35, the length of projection of theshear pin 35 b is continuously adjustable, or variable, through controlof current applied to the solenoid 35 a by means of the electric controlunit ECU, whereby the energy absorption load of the energy-absorbingmechanism 30; i.e., a load generated when the shear pin 35 b shears thecurved plate 34, can be continuously adjusted. Notably, an energyabsorption load that is attained when the support pin 32 draws out anddeforms the curved plate 34 is constant and thus invariable, and isgenerated substantially simultaneously with the event of the shear pin35 b shearing the curved plate 34.

[0031] As shown in FIG. 1, the seat belt device 40 includes a seat belt41; a tongue plate 42; a buckle 43; a shoulder belt anchor 44; and aretractor 45, which contains a pretensioner mechanism and a forcelimiter mechanism. A switch S1 contained in the buckle 43 detects thepresence/absence of the tongue plate 42, thereby detecting whether ornot the driver H wears the seat belt 41.

[0032] The pretensioner mechanism instantaneously takes up the seat belt41 at the initial stage of a front collision event of the vehicle so asto firmly restrain the body of the driver H. The force limiter mechanismfunctions as follows: when, during a front collision event of thevehicle, the driver H moves frontward as a reaction to impact, themechanism slightly loosens restraint of the seat belt 41 so as to reducethe load imposed on the chest of the driver H to a set load F3.

[0033] The electric control unit ECU controls the operation of the airbag mechanism 20 and the energy-absorbing mechanism 30 in accordancewith the kinetic energy (E) of the driver H and whether or not thedriver H wears the seat belt 41. The electric control unit ECU iselectrically connected to the air bag device 20 and the energy-absorbingmechanism 30 as well as to the switch S1 contained in the buckle 43 fordetecting whether or not the driver H wears the seat belt 41, aseating-position sensor (or weight sensor) S2 for detecting the physique(weight M) of the driver H, and a vehicle speed sensor S3 for detectinga vehicle speed (V).

[0034] The electric control unit ECU increases/decreases, in the samedirection, the energy absorption loads F1 and F2 of the air bag device20 and the energy-absorbing mechanism 30 in accordance with the kineticenergy (E=½·M·V²) of the driver H, which is calculated on the basis ofdetection signals from the seating-position sensor S2 and the vehiclespeed sensor S3. Specifically, when the kinetic energy E of the driver His greater than an assumed value, the electric control unit ECU sets,higher than an assumed load Fo, the energy absorption loads F1 and F2 ofthe air bag device 20 and the energy-absorbing mechanism 30, asrepresented by the dot-and-dash line in FIG. 7(a). When the kineticenergy E of the driver H is less than the assumed value, the electriccontrol unit ECU sets, lower than the assumed load Fo (but higher than aload F4 that is generated by the energy-absorbing means provided on thesteering wheel 11), the energy absorption loads F1 and F2 of the air bagdevice 20 and the energy-absorbing mechanism 30, as represented by thebroken line in FIG. 7(a).

[0035] The electric control unit ECU can control the energy absorptionloads F1 and F2 of the air bag device 20 and the energy-absorbingmechanism 30 on the basis of a detection signal from the switch S1contained in the buckle 43. Specifically, the energy absorption loads F1and F2 are set low as shown in FIG. 7(a) when the driver H wears theseat belt 41, and are set high as shown in FIG. 8 when the driver H doesnot wear the seat belt 41. In control by the electric control unit ECU,in order to trigger the operation of the air bag device 20simultaneously with or prior to the operation of the energy-absorbingmechanism 30, the energy absorption load F2 of the energy-absorbingmechanism 30 is set equal to or higher than the energy absorption loadF1 of the air bag device 20 (F2≧F1).

[0036] In operation of the thus-configured embodiment, during a frontcollision event of the vehicle under a condition of the driver H wearingthe seat belt 41, as the chest of the driver H moves, the seat beltdevice 40 functions, and also the air bag device 20 incorporated in thesteering wheel 11, the mechanical energy-absorbing means provided on thesteering wheel 11, and the energy-absorbing mechanism 30 mounted betweenthe steering column 12 and the vehicle body (not shown) operatesequentially, thereby yielding the performance (energy absorption loadsF3, F1, F4, and F2) as schematically shown in FIG. 7(a) and thusabsorbing the impact energy of the driver H.

[0037] During a front collision event of the vehicle in a condition ofthe driver H not wearing the seat belt 41, as the chest of the driver Hmoves, the air bag device 20 incorporated in the steering wheel 11, themechanical energy-absorbing means provided on the steering wheel 11, andthe energy-absorbing mechanism 30 mounted between the steering column 12and the vehicle body (not shown) operate sequentially, thereby yieldingthe performance (energy absorption loads F1, F4, and F2) asschematically shown in FIG. 8 and thus absorbing the impact energy ofthe driver H.

[0038] In the present embodiment, when the kinetic energy of the driverH is greater than an assumed value (for example, when the driver has aphysique Hr greater than the standard physique as shown in FIG. 1 orwhen the vehicle speed V upon occurrence of a front collision of thevehicle is higher than an assumed value), as represented by thedot-and-dash line in FIG. 7(a), the energy absorption loads F1 and F2 ofthe air bag device 20 and the energy-absorbing mechanism 30 are sethigher than the assumed load Fo (represented by a solid line).

[0039] When the kinetic energy of the driver H is less than the assumedvalue (for example, when the driver has a physique Hf less than thestandard physique as shown in FIG. 1 or when the vehicle speed V uponoccurrence of a front collision of the vehicle is lower than the assumedvalue), as represented by the broken line in FIG. 7(a), the energyabsorption loads F1 and F2 of the air bag device 20 and theenergy-absorbing mechanism 30 are set lower than the assumed load Fo(represented by a solid line).

[0040] Thus, as compared with a typical comparative example (the air bagdevice 20 is of a variable energy absorption load type, whereas theenergy-absorbing mechanism 30 is of a fixed energy absorption load type;i.e., F2=Fo (constant)) schematically shown in FIG. 7(b), the presentembodiment is characterized as follows: in the case where the energyabsorption loads F1 and F2 become high as represented by thedot-and-dash line in FIG. 7(a), the loads F1 and F2 can be reduced by aload Δf1 shown in FIG. 7; and in the case where the energy absorptionloads F1 and F2 become low as represented by the broken line in FIG.7(a), the loads F1 and F2 can be reduced by a load Δf2.

[0041] Thus, as compared with the above-mentioned comparative example,in any cases, the present embodiment can effectively absorb impactenergy while an energy absorption load that is imposed on the driver Hduring a vehicle collision event is suppressed to a low value. As shownin FIG. 7, such an effect can be attained without increasing therespective working strokes of the air bag device 20 and theenergy-absorbing mechanism 30, so that the easiness of mounting of theair bag device 20 and the energy-absorbing mechanism 30 onto the vehicleis not impaired.

[0042] As compared with another comparative example in which the air bagdevice 20 is of a fixed energy absorption load type; i.e., F1=Fo(constant), for a reason similar to that described above, in any cases,the present embodiment can effectively absorb impact energy while anenergy absorption load that is imposed on the driver H during a vehiclecollision event is suppressed to a low value. As compared with a furthercomparative example in which both of the air bag device 20 and theenergy-absorbing mechanism 30 are of a fixed energy absorption loadtype; i.e., F1=F2=Fo (constant), the present embodiment is characterizedas follows: in the case where the energy absorption loads F1 and F2become low as represented by the broken line in FIG. 7(a), the loads F1and F2 can be reduced by the load Δf2.

[0043] According to the present embodiment, the energy absorption loadsF1 and F2 of the air bag device 20 and the energy-absorbing mechanism 30are set low as schematically shown in FIG. 7(a) when the driver H wearsthe seat belt 41; and the energy absorption loads F1 and F2 are set highas schematically shown in FIG. 8 when the driver H does not wear theseat belt 41 (the energy absorption loads F1 and F2 of the air bagdevice 20 and the energy-absorbing mechanism 30 are increased so as tocompensate the loss of the energy absorption load F3, which couldotherwise be generated by the seat belt 41, resulting from a failure tofasten the seat belt 41). Thus, regardless of whether the seat belt 41is fastened, the impact energy of the driver H is reliably absorbed,whereby the driver H can be reliably protected.

[0044] Additionally, in the present embodiment, the mechanicalenergy-absorbing means is provided on the steering wheel 11 and cancooperatively absorb the impact energy of the driver H (the energyabsorption load F4 can be obtained). Thus, as compared with the casewhere the steering wheel 11 is not provided with the energy-absorbingmeans, the air bag device 20 and the energy-absorbing mechanism 30 canbe reduced in size (the energy absorption capability can be set to alower level) and thus the easiness of mounting of the device andmechanism onto the vehicle is improved.

[0045] According to the above-described embodiment, the energyabsorption loads F1 and F2 of the air bag device 20 and theenergy-absorbing mechanism 30 are varied continuously in the samedirection in accordance with the kinetic energy of the driver H.However, the present invention can be embodied as follows: the energyabsorption loads F1 and F2 of the air bag device 20 and theenergy-absorbing mechanism 30 are varied stepwise in the same directionin accordance with the kinetic energy of the driver H.

[0046] According to the above-described embodiment, during a frontcollision event of the vehicle, both of the air bag device 20 and theenergy-absorbing mechanism 30 operate. However, the present inventioncan be embodied as follows: when the kinetic energy of the driver issmall (for example, when the vehicle speed upon occurrence of a frontcollision of a vehicle is lower than a set value), for example, only theair bag device 20, only the energy-absorbing mechanism 30, or only themechanical energy-absorbing means provided on the steering wheel 11operates. In such a case, the vehicle can be readily repaired.

[0047] According to the above-described embodiment, the energyabsorption loads F1 and F2 of the air bag device 20 and theenergy-absorbing mechanism 30 are increased/decreased in the samedirection in accordance with the kinetic energy (E=½·M·V²) of the driverH that is calculated on the basis of detection signals from theseating-position sensor S2 and the vehicle speed sensor S3. However, thepresent invention can be embodied, for example, as follows: the energyabsorption loads F1 and F2 of the air bag device 20 and theenergy-absorbing mechanism 30 are increased/decreased in the samedirection in accordance with the kinetic energy (E=½·M·V²) of the driverH that is calculated on the basis of a detection signal from the vehiclespeed sensor S3 while the weight (M) of the driver H is assumed to beconstant. Alternatively, the energy absorption loads F1 and F2 can beincreased/decreased in accordance with a detection value from a Gsensor, a vehicle speed sensor, or a like sensor, or in accordance withthe result of calculation performed on the combination of such detectionvalues.

[0048] The above-described embodiment employs the air bag device 20incorporated in the steering wheel 11. However, the air bag device foruse in the present invention is not limited to the air bag device 20 ofthe above embodiment, but may be configured in any form so long as anair bag that is inflated and deployed between the steering wheel and anoccupant is provided. According to the above-described embodiment, thesteering column 12 and the energy-absorbing mechanism 30 constitute animpact-energy-absorption-type steering column. However, theimpact-energy-absorption-type steering column for use in the presentinvention is not limited thereto. For example, an energy-absorbingmechanism may be incorporated in a steering column itself.

1. An occupant protection apparatus comprising an air bag device fordeploying an air bag between a steering wheel and an occupant and animpact-energy-absorption-type steering column, and adapted to absorbimpact energy of the occupant during a vehicle collision event,characterized in that both the air bag device and theimpact-energy-absorption-type steering column are of a variable energyabsorption load type; and when the energy absorption loads of the airbag device and the impact-energy-absorption-type steering column arevaried, the energy absorption loads are varied in the same direction insuch a manner that the energy absorption load of theimpact-energy-absorption-type steering column is maintained equal to orgreater than the energy absorption load of the air bag device.
 2. Anoccupant protection apparatus according to claim 1, wherein both theenergy absorption loads of the air bag device and theimpact-energy-absorption-type steering column are set low when theoccupant wears his/her seat belt, and set high when the occupant doesnot wear his/her seat belt.
 3. An occupant protection apparatusaccording to claim 1, wherein the steering wheel comprisesenergy-absorbing means for absorbing impact energy.
 4. An occupantprotection apparatus according to claim 1, wherein, in the case of acondition under which the energy absorption loads are set low, at leastone of the air bag device and the impact-energy-absorption-type steeringcolumn is selected to absorb impact energy.
 5. An occupant protectionapparatus according to claim 3, wherein, in the case of a conditionunder which the energy absorption loads are set low, at least one of theair bag device, the impact-energy-absorption-type steering column, andthe energy-absorbing means is selected to absorb impact energy.
 6. Anoccupant protection apparatus comprising an air bag device for deployingan air bag between a steering wheel and an occupant and animpact-energy-absorption-type steering column, and adapted to absorbimpact energy of the occupant during a vehicle collision event,characterized in that both the air bag device and theimpact-energy-absorption-type steering column are of a variable energyabsorption load type capable of increasing and decreasing the energyabsorption load from an assumed energy absorption load in accordancewith kinetic energy of a driver; and when the energy absorption loads ofthe air bag device and the impact-energy-absorption-type steering columnare varied from the assumed energy absorption load, the energyabsorption loads are varied in the same direction.
 7. An occupantprotection apparatus according to claim 6, wherein both the assumedenergy absorption loads of the air bag device and theimpact-energy-absorption-type steering column are set low when theoccupant wears his/her seat belt, and set high when the occupant doesnot wear his/her seat belt.
 8. An occupant protection apparatusaccording to claim 6, wherein the steering wheel comprisesenergy-absorbing means for absorbing impact energy.
 9. An occupantprotection apparatus according to claim 6, wherein, in the case of acondition under which the energy absorption loads are set low, at leastone of the air bag device and the impact-energy-absorption-type steeringcolumn is selected to absorb impact energy.
 10. An occupant protectionapparatus according to claim 8, wherein, in the case of a conditionunder which the energy absorption loads are set low, at least one of theair bag device, the impact-energy-absorption-type steering column, andthe energy-absorbing means is selected to absorb impact energy.
 11. Anoccupant protection apparatus according to claim 2, wherein the steeringwheel comprises energy-absorbing means for absorbing impact energy. 12.An occupant protection apparatus according to claim 2, wherein, in thecase of a condition under which the energy absorption loads are set low,at least one of the air bag device and the impact-energy-absorption-typesteering column is selected to absorb impact energy.
 13. An occupantprotection apparatus according to claim 7, wherein the steering wheelcomprises energy-absorbing means for absorbing impact energy.
 14. Anoccupant protection apparatus according to claim 7, wherein, in the caseof a condition under which the energy absorption loads are set low, atleast one of the air bag device and the impact-energy-absorption-typesteering column is selected to absorb impact energy.